It is well known to those skilled in the art that aromatic hydrocarbons are a class of very important industrial chemicals which find a variety of uses in petrochemical industry. Recent efforts to convert gasoline to more valuable petrochemical products have therefore focused on the aromatization of gasoline to aromatic hydrocarbons by catalytic cracking in the presence of a catalyst. The aromatic hydrocarbons produced by the aromatization process include C.sub.6 to C.sub.8 hydrocarbons such as benzene, toluene and xylenes (hereinafter collectively referred to as BTX) which can be useful feedstocks for producing various organic compounds and polymers. However, heavier, less useful aromatic compounds are also produced during the aromatization process. It is, therefore, highly desirable to convert these compounds to the more useful BTX.
Though a metal oxide-promoted alumina such as Cr/Al.sub.2 O.sub.3 has been used as catalyst in a hydrodealkylation process, the conversion of a C.sub.9 + aromatic compound and the selectivity to BTX are generally not as high as one skilled in the art would desire. It is also well known to one skilled in the art that alumina is an acidic metal oxide containing acid sites. One of the possible reasons for such low conversion and low selectivity is probably due to the acidity of an alumina-based catalyst.
However, a catalyst used in the hydrodealkylation of these heavier aromatic compounds is generally deactivated in a rather short period because of depositions of carbonaceous material such as, for example, coke on the surface of the catalyst. Generally, the more active the catalyst is, the more rapid deposition of coke on the catalyst is observed.
Accordingly, there is an ever-increasing need to develop a catalyst and a process for converting these heavier and less useful aromatic compounds to the more valuable BTX hydrocarbons (hereinafter referred to as hydrodealkylation process) and, in the meantime, for suppressing the coke formation. Such development would also be a significant contribution to the art and to the economy.